C# Internal.FrameworkObject类代码示例

        // FindResourceInternal(fe/fce)  Defaults: none
        internal static object FindResourceInternal( 
            FrameworkElement        fe, 
            FrameworkContentElement fce,
            DependencyProperty      dp, 
            object                  resourceKey,
            object                  unlinkedParent,
            bool                    allowDeferredResourceReference,
            bool                    mustReturnDeferredResourceReference, 
            DependencyObject        boundaryElement,
            bool                    isImplicitStyleLookup, 
            out object              source) 
        {
            object value; 
            InheritanceBehavior inheritanceBehavior = InheritanceBehavior.Default;

            if( TraceResourceDictionary.IsEnabled )
            { 
                FrameworkObject element = new FrameworkObject(fe, fce);
 
                TraceResourceDictionary.Trace( 
                    TraceEventType.Start,
                    TraceResourceDictionary.FindResource, 
                     element.DO,
                     resourceKey );
            }
 
            try
            { 
 
                // First try to find the resource in the tree
                if (fe != null || fce != null || unlinkedParent != null) 
                {
                    value = FindResourceInTree(fe, fce, dp, resourceKey, unlinkedParent, allowDeferredResourceReference, mustReturnDeferredResourceReference, boundaryElement,
                                                out inheritanceBehavior, out source);
                    if (value != DependencyProperty.UnsetValue) 
                    {
                        return value; 
                    } 

                } 

                // Then we try to find the resource in the App's Resources
                Application app = Application.Current;
                if (app != null && 
                    (inheritanceBehavior == InheritanceBehavior.Default ||
                     inheritanceBehavior == InheritanceBehavior.SkipToAppNow || 
                     inheritanceBehavior == InheritanceBehavior.SkipToAppNext)) 
                {
                    value = app.FindResourceInternal(resourceKey, allowDeferredResourceReference, mustReturnDeferredResourceReference); 
                    if (value != null)
                    {
                        source = app;
 
                        if( TraceResourceDictionary.IsEnabled )
                        { 
                            TraceResourceDictionary.TraceActivityItem( 
                                TraceResourceDictionary.FoundResourceInApplication,
                                 resourceKey, 
                                value );
                        }

                        return value; 
                    }
                } 
 
                // Then we try to find the resource in the SystemResources but that is only if we aren't
                // doing an implicit style lookup. Implicit style lookup will stop at the app. 
                if (!isImplicitStyleLookup &&
                    inheritanceBehavior != InheritanceBehavior.SkipAllNow &&
                    inheritanceBehavior != InheritanceBehavior.SkipAllNext)
                { 
                    value = SystemResources.FindResourceInternal(resourceKey, allowDeferredResourceReference, mustReturnDeferredResourceReference);
                    if (value != null) 
                    { 
                        source = SystemResourceHost.Instance;
 
                        if( TraceResourceDictionary.IsEnabled )
                        {
                            TraceResourceDictionary.TraceActivityItem(
                                TraceResourceDictionary.FoundResourceInTheme, 
                                source,
                                resourceKey, 
                                value ); 
                        }
 

                        return value;
                    }
                } 
            }
            finally 
            { 
                if( TraceResourceDictionary.IsEnabled )
                { 
                    FrameworkObject element = new FrameworkObject(fe, fce);

                    TraceResourceDictionary.Trace(
                        TraceEventType.Stop, 
                        TraceResourceDictionary.FindResource,
//.........这里部分代码省略.........

        /// <summary>
        /// </summary> 
        internal static void InvalidateOnInheritablePropertyChange(
            FrameworkElement              fe, 
            FrameworkContentElement       fce, 
            InheritablePropertyChangeInfo info,
            bool                          skipStartNode) 
        {
            DependencyProperty dp = info.Property;
            FrameworkObject fo = new FrameworkObject(fe, fce);
            Debug.Assert(fo.IsValid, "Node with the resources change notification must be an FE or an FCE."); 

            if (HasChildren(fe, fce)) 
            { 
                // Spin up a DescendentsWalker only when
                // the current node has children to walk 

                DependencyObject d = fo.DO;

                DescendentsWalker<InheritablePropertyChangeInfo> walker = new DescendentsWalker<InheritablePropertyChangeInfo>( 
                    TreeWalkPriority.LogicalTree, InheritablePropertyChangeDelegate, info);
 
                walker.StartWalk(d, skipStartNode); 
            }
            else if (!skipStartNode) 
            {
                // Degenerate case when the current node is a leaf node and has no children.
                // If the current node needs a notification, do so now.
                OnInheritablePropertyChanged(fo.DO, info); 
            }
        } 

 // raise the InheritedPropertyChanged event to mentees.  Called from FE/FCE
 // OnPropertyChanged
 internal static void OnInheritedPropertyChanged(DependencyObject d, 
                                     ref InheritablePropertyChangeInfo info,
                                     InheritanceBehavior inheritanceBehavior) 
 { 
     if (inheritanceBehavior == InheritanceBehavior.Default || IsForceInheritedProperty(info.Property))
     { 
         FrameworkObject fo = new FrameworkObject(d);
         fo.OnInheritedPropertyChanged(ref info);
     }
 } 

        /// <summary>
        ///     Invalidate inheritable properties and resource 
        ///     references during a tree change operation. 
        /// </summary>
        internal static void InvalidateOnTreeChange( 
            FrameworkElement        fe,
            FrameworkContentElement fce,
            DependencyObject        parent,
            bool                    isAddOperation) 
        {
            Debug.Assert(fe != null || fce != null, "Node with the tree change notification must be an FE or an FCE."); 
            Debug.Assert(parent != null, "Must have a parent that the current node is connected to or disconnected from."); 

            // If the tree change is for a non-FE/FCE parent then we need to find 
            // the nearest FE/FCE parent inorder to propagate inheritance correctly.
            FrameworkObject parentFO = new FrameworkObject(parent);
            if (!parentFO.IsValid)
            { 
                parent = parentFO.FrameworkParent.DO;
            } 
 
            // We're interested in changes to the Template property that occur during
            // the walk - if the template has changed we don't need to invalidate 
            // template-driven properties a second time.  The HasTemplateChanged property
            // is cleared on the first visit to each node, so that it means "template
            // changed during the walk".  But one relevant node isn't visited during
            // the walk - the templated parent of the initial node.  So we handle that now. 
            FrameworkObject fo = new FrameworkObject(fe, fce);
 
            // Synchronize the ShouldLookupImplicitStyles flag with respect to the parent here 
            // because for the root node of a tree change UpdateStyleProperty happens right here
            // in this method. And we need to have synchrnozed the ShouldLookupImplicitStyles 
            // before we re-query the Style property.

            if (isAddOperation)
            { 
                fo.SetShouldLookupImplicitStyles();
            } 
 
            fo.Reset(fo.TemplatedParent);
            fo.HasTemplateChanged = false; 

            DependencyObject d = (fe != null) ? (DependencyObject)fe : (DependencyObject)fce;

            // during a tree walk to invalidate inherited properties, we typically 
            // call UpdateStyle from FE/FCE.InvalidateTreeDependentProperties.  But
            // for the root element of the tree change, we need to record old values 
            // for inherited properties before we've updated the inheritance parent; 
            // so do the updatestyle here before we record old values so that we
            // capture any updates provided by styles. 
            if (fe != null)
            {
                if (fe.IsInitialized && !fe.HasLocalStyle)
                { 
                    // Clear the HasStyleChanged flag
                    fe.HasStyleChanged = false; 
                    fe.HasStyleInvalidated = false; 
                    fe.HasTemplateChanged = false;
 
                    fe.AncestorChangeInProgress = true;
                    fe.UpdateStyleProperty();
                    fe.AncestorChangeInProgress = false;
                } 
            }
            else 
            { 
                if (!fce.HasLocalStyle)
                { 
                    // Clear the HasStyleChanged flag
                    fce.HasStyleChanged = false;
                    fce.HasStyleInvalidated = false;
 
                    fce.AncestorChangeInProgress = true;
                    fce.UpdateStyleProperty(); 
                    fce.AncestorChangeInProgress = false; 
                }
            } 

            if (HasChildren(fe, fce))
            {
                // Spin up a DescendentsWalker only when 
                // the current node has children to walk
 
                // If there is another tree walk that has already visited the 
                // current node then we do not need to re-walk its sub-tree.
                FrameworkContextData fcdata = FrameworkContextData.From(d.Dispatcher); 
                if (!fcdata.WasNodeVisited(d, TreeChangeDelegate))
                {
                    // The TreeChangeInfo object is used here to track
                    // information that we have because we're doing a tree walk. 
                    TreeChangeInfo parentInfo = new TreeChangeInfo(d, parent, isAddOperation);
 
                    // PrePostDescendentsWalker is used instead of the standard 
                    // DescendentsWalker because we need a "post" callback to know when
                    // to pop the parent's InheritableProperties cache from the stack. 
                    PrePostDescendentsWalker<TreeChangeInfo> walker = new PrePostDescendentsWalker<TreeChangeInfo>(
                        TreeWalkPriority.LogicalTree, TreeChangeDelegate, TreeChangePostDelegate, parentInfo);

                    fcdata.AddWalker(TreeChangeDelegate, walker); 

//.........这里部分代码省略.........

        /// <summary>
        ///     Process a resource change for the given DependencyObject. 
        ///     Return true if the DO has resource references.
        /// </summary> 
        internal static void OnResourcesChanged( 
            DependencyObject    d,
            ResourcesChangeInfo info, 
            bool raiseResourceChangedEvent)
        {
            Debug.Assert(d != null, "Must have non-null current node");
 
            bool containsTypeOfKey = info.Contains(d.DependencyObjectType.SystemType, true /*isImplicitStyleKey*/);
            bool isSystemResourcesChange = info.IsThemeChange; 
            bool isStyleResourcesChange = info.IsStyleResourcesChange; 
            bool isTemplateResourcesChange = info.IsTemplateResourcesChange;
            bool isContainer = (info.Container == d); 

            FrameworkObject fo = new FrameworkObject(d);

            // If a resource dictionary changed above this node then we need to 
            // synchronize the ShouldLookupImplicitStyles flag with respect to
            // our parent here. 
 
            if (info.IsResourceAddOperation || info.IsCatastrophicDictionaryChange)
            { 
                fo.SetShouldLookupImplicitStyles();
            }

            // Invalidate implicit and explicit resource 
            // references on current instance
            if (fo.IsFE) 
            { 
                // If this is a FrameworkElement
                FrameworkElement fe = fo.FE; 
                fe.HasStyleChanged = false; // detect style changes that arise from work done here
                fe.HasStyleInvalidated = false;
                fe.HasTemplateChanged = false; // detect template changes that arise from work done here
 
                if (fe.HasResourceReference)
                { 
 
                    // Invalidate explicit ResourceReference properties on the current instance.
                    // If the Style property comes from an implicit resource reference that 
                    // will be invalidated too.
                    InvalidateResourceReferences(fe, info);

                    // There is no need to invalidate the resources references on the 
                    // container object if this call is a result of a style/template
                    // change. This is because the style/template change would have 
                    // already invalidated all the container dependents and all the 
                    // resources references on the container would have been a part of it.
                    if ((!isStyleResourcesChange && !isTemplateResourcesChange ) || !isContainer) 
                    {
                        InvalidateStyleAndReferences(d, info, containsTypeOfKey);
                    }
                } 
                else if (containsTypeOfKey &&
                        (fe.HasImplicitStyleFromResources || fe.Style == FrameworkElement.StyleProperty.GetMetadata(fe.DependencyObjectType).DefaultValue)) 
                { 
                    // If The Style property on the given instance has been
                    // fetched by an implicit resource lookup then 
                    // it needs to be invalidated. Also we need to do this
                    // invalidation only if the dictionary/resources that is
                    // changing matches the implicit key used for the resource lookup.
 
                    // The StyleProperty does not need to be invalidated if this
                    // call is the result of a style change 
                    if (!isStyleResourcesChange || !isContainer) 
                    {
                        fe.UpdateStyleProperty(); 
                    }
                }

                // If there has been a Theme change then 
                // invalidate the ThemeStyleProperty
                if (isSystemResourcesChange) 
                { 
                    fe.UpdateThemeStyleProperty();
                } 

                // Raise the ResourcesChanged Event so that ResourceReferenceExpressions
                // on non-[FE/FCE] (example Freezables) listening for this can then update
                // their values 
                if (raiseResourceChangedEvent && fe.PotentiallyHasMentees)
                { 
                    fe.RaiseClrEvent(FrameworkElement.ResourcesChangedKey, new ResourcesChangedEventArgs(info)); 
                }
            } 
            else
            {
                // If this is a FrameworkContentElement
                FrameworkContentElement fce = fo.FCE; 
                fce.HasStyleChanged = false; // detect style changes that arise from work done here
                fce.HasStyleInvalidated = false; 
 
                if (fce.HasResourceReference)
                { 
                    // Invalidate explicit ResourceReference properties on the current instance.
                    // If the Style property comes from an implicit resource reference that
                    // will be invalidated too.
//.........这里部分代码省略.........

        /// <summary> 
        ///     Determine if the current DependencyObject is a candidate for 
        ///     producing inheritable values
        /// </summary> 
        /// <remarks>
        ///     This is called by both InvalidateTree and GetValueCore
        /// </remarks>
        internal static bool IsInheritanceNode( 
            DependencyObject    d,
            DependencyProperty  dp, 
        out InheritanceBehavior inheritanceBehavior) 
        {
            // Assume can continue search 
            inheritanceBehavior = InheritanceBehavior.Default;

            // Get Framework metadata (if exists)
            FrameworkPropertyMetadata metadata = dp.GetMetadata(d.DependencyObjectType) as FrameworkPropertyMetadata; 

            // Check for correct type of metadata 
            if (metadata != null) 
            {
                FrameworkObject fo = new FrameworkObject(d); 

                if (fo.IsValid)
                {
                    // If parent is a Framework type, then check if it is at a 
                    // tree separation boundary. Stop inheritance at the boundary unless
                    // overridden by the medata.OverridesInheritanceBehavior flag. 
 
                    // GetValue from Parent only if instance is not a TreeSeparator
                    // or fmetadata.OverridesInheritanceBehavior is set to override separated tree behavior 
                    if (fo.InheritanceBehavior != InheritanceBehavior.Default && !metadata.OverridesInheritanceBehavior)
                    {
                        // Hit a tree boundary
                        inheritanceBehavior = fo.InheritanceBehavior; 
                    }
                } 
                else 
                {
                    // If not a Framework type, then, this isn't an inheritance node. 
                    // Only Framework types know how to inherit

                    return false;
                } 

                // Check if metadata is marked as inheritable 
                if (metadata.Inherits) 
                {
                    return true; 
                }
            }

            // Not a framework type with inheritable metadata 
            return false;
        } 

        /// <summary> 
        ///     Invalidate all the properties in the given
        ///     collection of inheritable properties 
        /// </summary> 
        /// <remarks>
        ///     This method is called during an [FE/FCE].OnAncestorChange 
        /// </remarks>
        internal static FrugalObjectList<DependencyProperty> InvalidateTreeDependentProperties(
            TreeChangeInfo                       info,
            FrameworkElement                     fe, 
            FrameworkContentElement              fce,
            Style                                selfStyle, 
            Style                                selfThemeStyle, 
            ref ChildRecord                      childRecord,
            bool                                 isChildRecordValid, 
            bool                                 hasStyleChanged,
            bool                                 isSelfInheritanceParent)
        {
            Debug.Assert(fe != null || fce != null, "Must have non-null current node"); 
            DependencyObject d = fe != null ? (DependencyObject)fe : (DependencyObject)fce;
            FrameworkObject fo = new FrameworkObject(fe, fce); 
 
            // Pull up the parent's InheritableProperties cache
            FrugalObjectList<DependencyProperty> parentInheritableProperties = info.InheritablePropertiesStack.Peek(); 

            // Loop through all cached inheritable
            // to see if they should be invalidated.
            int inheritablePropertiesCount = parentInheritableProperties  != null ? parentInheritableProperties.Count : 0; 

            FrugalObjectList<DependencyProperty> currentInheritableProperties = null; 
            if (HasChildren(fe, fce)) 
            {
                currentInheritableProperties = new FrugalObjectList<DependencyProperty>(inheritablePropertiesCount); 
            }

            info.ResetInheritableValueIndexer();
 
            for (int i = 0; i < inheritablePropertiesCount; i++)
            { 
                DependencyProperty inheritableProperty = parentInheritableProperties[i]; 

                Debug.Assert(inheritableProperty.IsPotentiallyInherited, "if we got here, it means that this property is inheritable by someone"); 

                PropertyMetadata metadata = inheritableProperty.GetMetadata(d);

                // Invalidate only properties that are marked as inheritable. 
                // These are the ones that will be affected by an ancestor changes.
                if (metadata.IsInherited) 
                { 
                    FrameworkPropertyMetadata fMetadata = (FrameworkPropertyMetadata)metadata;
 
                    bool changed = InvalidateTreeDependentProperty(info, d, ref fo, inheritableProperty, fMetadata,
                        selfStyle, selfThemeStyle, ref childRecord, isChildRecordValid, hasStyleChanged, isSelfInheritanceParent);

                    // If a change is detected then add the inheritable property to 
                    // the current list so that it can be used to invalidate further children
                    if (changed && currentInheritableProperties != null) 
                    { 
                        Debug.Assert(!currentInheritableProperties.Contains(inheritableProperty), "InheritableProperties list should not have duplicates");
 
                        // Children do not need to inherit properties across a tree boundary
                        // unless the property is set to override this behavior.

                        if (!SkipNow(fo.InheritanceBehavior) || fMetadata.OverridesInheritanceBehavior) 
                        {
                            currentInheritableProperties.Add(inheritableProperty); 
                        } 
                    }
                } 
            }

            return currentInheritableProperties;
        } 

        // Given a FrameworkElement and a name string, this routine will try to find
        //  a node with Name property set to the given name.  It will search all 
        //  the child logical tree nodes of the given starting element.
        // If the name string is null or an empty string, the given starting element 
        //  is returned. 
        // If the name is found on a FrameworkContentElement, an exception is thrown
        // If the name is not found attached to anything, an exception is thrown 
        internal static FrameworkElement FindNamedFrameworkElement( FrameworkElement startElement, string targetName )
        {
            FrameworkElement targetFE = null;
 
            if( targetName == null || targetName.Length == 0 )
            { 
                targetFE = startElement; 
            }
            else 
            {
                DependencyObject targetObject = null;

                targetObject = LogicalTreeHelper.FindLogicalNode( startElement, targetName ); 

                if( targetObject == null ) 
                { 
                    throw new ArgumentException( SR.Get(SRID.TargetNameNotFound, targetName));
                } 

                FrameworkObject fo = new FrameworkObject(targetObject);
                if( fo.IsFE )
                { 
                    targetFE = fo.FE;
                } 
                else 
                {
                    throw new InvalidOperationException(SR.Get(SRID.NamedObjectMustBeFrameworkElement, targetName)); 
                }
            }

            return targetFE; 
        }

 /// <summary>
 /// Find the element given name
 /// </summary>
 object INameScope.FindName(string name)
 {
     // _templatedParent is null if template.LoadContent() was responsible
     if (_templatedParent != null)
     {
         FrameworkObject fo = new FrameworkObject(_templatedParent);
         
         Debug.Assert(fo.IsFE);
         if (fo.IsFE)
         {
             return StyleHelper.FindNameInTemplateContent(fo.FE, name, fo.FE.TemplateInternal);
         }
         else
         {
             return null;
         }
     }
     else
     {
         if (_nameMap == null || name == null || name == String.Empty)
             return null;
         
         return _nameMap[name];
     }
 }

        internal static bool GetFrameworkParent(FrameworkContentElement current, out FrameworkElement feParent, out FrameworkContentElement fceParent)
        { 
            FrameworkObject fo = new FrameworkObject(null, current);

            fo = fo.FrameworkParent;
 
            feParent = fo.FE;
            fceParent = fo.FCE; 
 
            return fo.IsValid;
        } 

        // Fetchs the specified childRecord for the given template.  Returns true if successful.
        internal static void GetTemplatedParentChildRecord( 
            DependencyObject templatedParent,
            int childIndex, 
            out ChildRecord childRecord, 
            out bool isChildRecordValid)
        { 
            FrameworkTemplate templatedParentTemplate = null;
            isChildRecordValid = false;
            childRecord = new ChildRecord();    // CS0177
 
            if (templatedParent != null)
            { 
                FrameworkObject foTemplatedParent = new FrameworkObject(templatedParent, true); 

                Debug.Assert( foTemplatedParent.IsFE ); 

                // This node is the result of a style expansion

                // Pick the owner for the VisualTree that generated this node 
                templatedParentTemplate = foTemplatedParent.FE.TemplateInternal;
 
                Debug.Assert(templatedParentTemplate != null , 
                    "If this node is the result of a VisualTree expansion then it should have a parent template");
 
                // Check if this Child Index is represented in FrameworkTemplate
                if (templatedParentTemplate != null && ((0 <= childIndex) && (childIndex < templatedParentTemplate.ChildRecordFromChildIndex.Count)))
                {
                    childRecord = templatedParentTemplate.ChildRecordFromChildIndex[childIndex]; 
                    isChildRecordValid = true;
                } 
 
            }
        } 

        // Search the parent chain for a [Data|Table]Template in a ResourceDictionary. 
        private static object FindTemplateResourceInTree(DependencyObject target, ArrayList keys, int exactMatch, ref int bestMatch)
        { 
            Debug.Assert(target != null, "Don't call FindTemplateResource with a null target object"); 

            ResourceDictionary table; 
            object resource = null;

            FrameworkObject fo = new FrameworkObject(target);
            Debug.Assert(fo.IsValid, "Don't call FindTemplateResource with a target object that is neither a FrameworkElement nor a FrameworkContentElement"); 

            while (fo.IsValid) 
            { 
                object candidate;
 
                // -------------------------------------------
                //  Lookup ResourceDictionary on the current instance
                // -------------------------------------------
 
                // Fetch the ResourceDictionary
                // for the given target element 
                table = GetInstanceResourceDictionary(fo.FE, fo.FCE); 
                if( table != null )
                { 
                    candidate = FindBestMatchInResourceDictionary( table, keys, exactMatch, ref bestMatch );
                    if (candidate != null)
                    {
                        resource = candidate; 
                        if (bestMatch < exactMatch)
                        { 
                            // Exact match found, stop here. 
                            return resource;
                        } 
                    }
                }

                // ------------------------------------------- 
                //  Lookup ResourceDictionary on the current instance's Style, if one exists.
                // ------------------------------------------- 
 
                table = GetStyleResourceDictionary(fo.FE, fo.FCE);
                if( table != null ) 
                {
                    candidate = FindBestMatchInResourceDictionary( table, keys, exactMatch, ref bestMatch );
                    if (candidate != null)
                    { 
                        resource = candidate;
                        if (bestMatch < exactMatch) 
                        { 
                            // Exact match found, stop here.
                            return resource; 
                        }
                    }
                }
 
                // -------------------------------------------
                //  Lookup ResourceDictionary on the current instance's Theme Style, if one exists. 
                // ------------------------------------------- 

                table = GetThemeStyleResourceDictionary(fo.FE, fo.FCE); 
                if( table != null )
                {
                    candidate = FindBestMatchInResourceDictionary( table, keys, exactMatch, ref bestMatch );
                    if (candidate != null) 
                    {
                        resource = candidate; 
                        if (bestMatch < exactMatch) 
                        {
                            // Exact match found, stop here. 
                            return resource;
                        }
                    }
                } 

                // ------------------------------------------- 
                //  Lookup ResourceDictionary on the current instance's Template, if one exists. 
                // -------------------------------------------
 
                table = GetTemplateResourceDictionary(fo.FE, fo.FCE);
                if( table != null )
                {
                    candidate = FindBestMatchInResourceDictionary( table, keys, exactMatch, ref bestMatch ); 
                    if (candidate != null)
                    { 
                        resource = candidate; 
                        if (bestMatch < exactMatch)
                        { 
                            // Exact match found, stop here.
                            return resource;
                        }
                    } 
                }
 
                // If the current element for resource lookup is marked such then abort 
                // lookup because resource lookup does not span tree boundaries
                if (fo.IsValid && TreeWalkHelper.SkipNext(fo.InheritanceBehavior)) 
                {
                    break;
                }
 
//.........这里部分代码省略.........

        // FindResourceInTree(fe/fce)  Defaults: none
        internal static object FindResourceInTree( 
            FrameworkElement        feStart,
            FrameworkContentElement fceStart,
            DependencyProperty      dp,
            object                  resourceKey, 
            object                  unlinkedParent,
            bool                    allowDeferredResourceReference, 
            bool                    mustReturnDeferredResourceReference, 
            DependencyObject        boundaryElement,
            out InheritanceBehavior inheritanceBehavior, 
            out object              source)
        {
            FrameworkObject startNode = new FrameworkObject(feStart, fceStart);
            FrameworkObject fo = startNode; 
            object value;
            Style style; 
            FrameworkTemplate frameworkTemplate; 
            Style themeStyle;
            int loopCount = 0; 
            bool hasParent = true;
            inheritanceBehavior = InheritanceBehavior.Default;

            while (hasParent) 
            {
                Debug.Assert(startNode.IsValid || unlinkedParent != null, 
                              "Don't call FindResource with a null fe/fce and unlinkedParent"); 

                if (loopCount > ContextLayoutManager.s_LayoutRecursionLimit) 
                {
                    // We suspect a loop here because the loop count
                    // has exceeded the MAX_TREE_DEPTH expected
                    throw new InvalidOperationException(SR.Get(SRID.LogicalTreeLoop)); 
                }
                else 
                { 
                    loopCount++;
                } 

                // -------------------------------------------
                //  Lookup ResourceDictionary on the current instance
                // ------------------------------------------- 

                style = null; 
                frameworkTemplate = null; 
                themeStyle = null;
 
                if (fo.IsFE)
                {
                    FrameworkElement fe = fo.FE;
 
                    value = fe.FindResourceOnSelf(resourceKey, allowDeferredResourceReference, mustReturnDeferredResourceReference);
                    if (value != DependencyProperty.UnsetValue) 
                    { 
                        source = fe;
 
                        if( TraceResourceDictionary.IsEnabled )
                        {
                            TraceResourceDictionary.TraceActivityItem(
                                TraceResourceDictionary.FoundResourceOnElement, 
                                source,
                                resourceKey, 
                                value ); 
                        }
 
                        return value;
                    }

                    if ((fe != startNode.FE) || StyleHelper.ShouldGetValueFromStyle(dp)) 
                    {
                        style = fe.Style; 
                    } 
                    // Fetch the Template
                    if ((fe != startNode.FE) || StyleHelper.ShouldGetValueFromTemplate(dp)) 
                    {
                        frameworkTemplate = fe.TemplateInternal;
                    }
                    // Fetch the ThemeStyle 
                    if ((fe != startNode.FE) || StyleHelper.ShouldGetValueFromThemeStyle(dp))
                    { 
                        themeStyle = fe.ThemeStyle; 
                    }
                } 
                else if (fo.IsFCE)
                {
                    FrameworkContentElement fce = fo.FCE;
 
                    value = fce.FindResourceOnSelf(resourceKey, allowDeferredResourceReference, mustReturnDeferredResourceReference);
                    if (value != DependencyProperty.UnsetValue) 
                    { 
                        source = fce;
 
                        if( TraceResourceDictionary.IsEnabled )
                        {
                            TraceResourceDictionary.TraceActivityItem(
                                TraceResourceDictionary.FoundResourceOnElement, 
                                source,
                                resourceKey, 
                                value ); 
                        }
//.........这里部分代码省略.........

        internal static FrameworkObject GetContainingFrameworkElement(DependencyObject current)
        {
            FrameworkObject fo = new FrameworkObject(current);

            while (!fo.IsValid && fo.DO != null)
            {
                // The current object is neither a FrameworkElement nor a
                // FrameworkContentElement.  We will now walk the "core"
                // tree looking for one.
                Visual visual;
                Visual3D visual3D;
                ContentElement ce;

                if ((visual = fo.DO as Visual) != null)
                {
                    fo.Reset(VisualTreeHelper.GetParent(visual));
                }
                else if ((ce = fo.DO as ContentElement) != null)
                {
                    fo.Reset(ContentOperations.GetParent(ce));
                }
                else if ((visual3D = fo.DO as Visual3D) != null)
                {
                    fo.Reset(VisualTreeHelper.GetParent(visual3D));
                }
                else
                {
                    // The parent could be an application.
                    fo.Reset(null);
                }
            }

            return fo;
        }

        // raise the SourceUpdatedEvent event (explicit polymorphism)
        internal static void OnSourceUpdated(DependencyObject d, DependencyProperty dp)
        {
            DataTransferEventArgs args = new DataTransferEventArgs(d, dp);
            args.RoutedEvent = Binding.SourceUpdatedEvent;
            FrameworkObject fo = new FrameworkObject(d);

            if (!fo.IsValid && d != null)
            {
                fo.Reset(Helper.FindMentor(d));
            }

            fo.RaiseEvent(args);
        }